The mechanisms of outflow of aqueous humor and the structural details of the tissues involved in that mechanism are controversial. This problem will be addressed through a tri-directional investigation. The primary goal of this investigation is to clarify the structural and functional correlates of aqueous outflow in the developing and adult eye of higher primates. Additionally, it is hoped that insights may be gained into the phylogenetic background of the aqueous outflow system. Information derived from such studies may well contribute toward the prevention and/or cure of glaucoma. First, the relationship between normal aqueous outflow and certain microstructural and metabolic aspects of the endothelial cells lining Schlemm's canal will be evaluated using constant pressure quantitative aqueous perfusion in living monkeys and freshly-excised post-mortem eyes from monkeys and adult human beings. Secondly, the developmental changes in the dynamics of aqueous outflow will be investigated by applying similar perfusion techniques to post- mortem eyes from fetal, neonatal, and immature monkeys; and to the extent that it becomes available (and laws permit) to human material. Thirdly, the functional significance of the unique structural character of the primate aqueous outflow system will be examined by comparing parameters of aqueous outflow and accommodative amplitude in primates, sub-primate nonaccommodating mammals, and birds with different ranges of accommodation. In correlation with these functional studies, detailed light and electron microscopic (transmission and scanning) evaluation will be made of specimens of the aqueous outflow system from eyes perfused in the experiments outlined above.